body{
    margin: 0;
    color: #333;
}
input{
    border: none;
    outline: none;
}
a{
    text-decoration: none;
    color: #333;
}
ul{
    padding: 0;
    list-style: none;
    margin: 0;
}
.clearfix::before{
    content: " ";
    display:block;
    clear: both;
}
.cover{

}
.container{
    width: 1200px;
    margin: 50px auto;
}
.course-tab{
    width: 1200px;
    height: 52px;
    background-color: #f5f5f5;
    margin-bottom: 20px;
    padding-left: 30px;
    border: 1px solid #eee;
    box-sizing: border-box;
}
.course-item{
    float: left;
    height: 50px;
    line-height: 50px;
    margin-right: 40px;
}
.course-item-lk{
    font-size: 14px;
}
.lk-current{
    color: #167ed9;
}
.course-card-list{
    width: 1225px;
    margin-left: -18px;
}
.card-item{
    float: left;
    width: 236px;
    margin:0 0 20px 9px;
    padding: 7px 7px 10px;
    border: 1px solid transparent;
    box-sizing: border-box;
    margin-bottom: 20px;
}
.card-item .card-lk{
    display:block;
    width: 100%;
    height: 100%;
    border: 1px solid #eee;
    position: relative;
}
.card-item .card-lk img{
    max-width: 100%;
}
.course-item-status{
    width: 100%;
    padding:10px;
    background-color: rgba(0,0,0,0.7);
    color: #fff;
    font-size: 14px;
    position: absolute;
    bottom:0;
    box-sizing: border-box;
}